1 files changed, 17 insertions, 11 deletions
diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h
index 9e20260611cc..aebbe65dab7e 100644
--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h
@@ -31,8 +31,8 @@
  *
  * To solve this issue, ISO 11898-1 introduces in section 11.3.3
  * "Transmitter delay compensation" a SSP (Secondary Sample Point)
- * equal to the distance, in time quanta, from the start of the bit
- * time on the TX pin to the actual measurement on the RX pin.
+ * equal to the distance from the start of the bit time on the TX pin
+ * to the actual measurement on the RX pin.
  *
  * This structure contains the parameters to calculate that SSP.
  *
@@ -44,8 +44,13 @@
  *                           |<------- TDCO ------->|
  *  |<----------- Secondary Sample Point ---------->|
  *
+ * To increase precision, contrary to the other bittiming parameters
+ * which are measured in time quanta, the TDC parameters are measured
+ * in clock periods (also referred as "minimum time quantum" in ISO
+ * 11898-1).
+ *
  * @tdcv: Transmitter Delay Compensation Value. The time needed for
- *	the signal to propagate, i.e. the distance, in time quanta,
+ *	the signal to propagate, i.e. the distance, in clock periods,
  *	from the start of the bit on the TX pin to when it is received
  *	on the RX pin. @tdcv depends on the controller modes:
  *
@@ -62,17 +67,18 @@
  *	TDC is disabled and all the values of this structure should be
  *	ignored.
  *
- * @tdco: Transmitter Delay Compensation Offset. Offset value, in time
- *	quanta, defining the distance between the start of the bit
- *	reception on the RX pin of the transceiver and the SSP
+ * @tdco: Transmitter Delay Compensation Offset. Offset value, in
+ *	clock periods, defining the distance between the start of the
+ *	bit reception on the RX pin of the transceiver and the SSP
  *	position such that SSP = @tdcv + @tdco.
  *
  * @tdcf: Transmitter Delay Compensation Filter window. Defines the
- *	minimum value for the SSP position in time quanta. If the SSP
- *	position is less than @tdcf, then no delay compensations occur
- *	and the normal sampling point is used instead. The feature is
- *	enabled if and only if @tdcv is set to zero (automatic mode)
- *	and @tdcf is configured to a value greater than @tdco.
+ *	minimum value for the SSP position in clock periods. If the
+ *	SSP position is less than @tdcf, then no delay compensations
+ *	occur and the normal sampling point is used instead. The
+ *	feature is enabled if and only if @tdcv is set to zero
+ *	(automatic mode) and @tdcf is configured to a value greater
+ *	than @tdco.
  */
 struct can_tdc {
 	u32 tdcv;